The present invention relates to enclosures for holding a plurality of printed circuit boards.
Card cages which contain and electrically interconnect a number of printed circuit boards are well-known. Typically these devices include a four-sided enclosure or a four-sided frame. A plurality of slotted tracks are located at the top and bottom of the enclosure to receive the opposite edges of the printed circuit boards. A back plane printed circuit board is usually mounted across the rear of the enclosure. The back plane provides a plurality of electrically interconnected terminals for mating with connectors on the printed circuit boards inserted in the tracks. Typically, a printed circuit board is inserted in the front end of the tracks and slid toward the rear of the enclosure until it makes good electrical contact with the connectors associated with those tracks.
In this fashion, different printed circuit board assemblies for a given piece of equipment may be held in place and electrically interconnected. One of the boards which is inserted in the enclosure may be the power supply for the remaining boards of the piece of equipment. In this case, the incoming electrical power is fed to this power supply board which then generates the various electrical power signals needed for the other boards. The signals are then supplied to the other boards through the back plane connectors.
One of the problems encountered in present day circuits, such as those using digital components, is that during the operation or maintenance of the equipment the operator may remove a printed circuit board from the chassis without turning off the electrical power. This may cause severe damage to the electrical components on the printed circuit board.